Stigonema scytonematoides N.L.Gardner

• Region

  West Indies

• Country

  Puerto Rico

• Locality

  north of Maricao, on rocks by the road

• Coordinates

  18.2137, -66.9872

• Geodetic Datum

  WGS84

• Distribution

  Map all specimens of this taxon

Determined by Francis Drouet

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57. Stigonema scytonematoides

Portion of an older filament with a single \ ege-
tative branch and, N, apical portion of a branch,
showing the character of lamellation of the

NEW YORK
BOTANICAL
CARDEN

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Determined by Francis Drouet

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Stigonema scytonematoides sp. nov.
Plate 22, figure 57

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Determined by Francis Drouet

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^ Filaments relatively short and straight, 125-175 p long, 23-
27 m thick, sparsely branched; branches similar to the main
frond, blunt and rounded; cells uniseriate, compressed-spheri-
cal, when old and dried drawn out somewhat at the poles, show-
ing distinct protoplasmic connections, bluish-green, homogene-
ous, 11-13 m diam.; heterocysts similar to the cells in shape, size,
and form; sheath thick, subgelatinous, faintly lamellose, particu-
larly so toward the apices where the laminae turn outward and
backwards from several cells, yellowish brown; hormogonia
short and blunt.

, :Growing on red earth north of Maricao, no. 1250, type; on
red earth near Mayagtiez, no. 88 Ore; on rocks by the road north
o,f Maricao, nos. 1245, 1250, and 1253<a; on rocks between Utu-
ado and Ad juntas, no. 1643; on rocks, Arroyo de los Corchos,
){0. 1715.	.

It is somewhat troublesome to distinguish the above new spe-
cies of Stigonema from certain species of Hassalia. There are
many filaments in botli genera which do not show branching.
Both have heterocysts very similar, being formed from an orig-
inal cell of the filament, whereas in many species of the genus
Stigonema for the most part the heterocyst is formed from a
part of an original cell produced by a longitudinal division. It
can .readily be distinguished, of course, when the branching can
be observed, and especially by the short, blunt, hormogoniferous
branches. Stigonema scytonematoides seems closely related to
S. elegans of this paper. ' The sheath is wider and lamellose, the
cells are more nearly spheres in form, and the diameter of the
filament is greater than in that species.

Determined by Francis Drouet

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Determined by Francis Drouet

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